Why did Theresa May call the UK elections?

It is the third time in two years that the citizens of the United Kingdom are called to the polls. After having chosen to leave the European Union during the referendum of the 23rd of June 2016, the 8th of June they're called to decide if Theresa May, the current Prime Minister and Conservative Party candidate, will represent them in the Brexit negotiations.
May, David Cameron's successorafter his resignation once he lost the battle to remain in Europe, has never faced national elections as the head of her party. The same goes for Jeremy Corbyn of the Labour Party, who according to electoral polls win, though the margin separating him from the Conservatives is growing smaller. Up to the last minute May denied she wanted to call snap elections, so why was there a sudden change of heart?

Why did Theresa May call the UK elections?

In front of 10 Downing Street, the UK government headquarters, on the 18th of April the Prime Minister declared that she felt obliged to call snap elections to give the country what it needs: "Certainty, stability and strong leadership". Because to obtain a good deal for the country's exit from the EU – so-called hard Brexit which would see the country leaving the common market and customs union – "there should be unity ... but there is division”. And, according to May, the fault lies with opposition parties' political games, which risk damaging the negotiations.

May wants to strengthen her party's majority in the House of Commons, Parliament's lower house; currently the Conservatives hold 330 seats out of 650 (versus 229 of the second party, Labour). According to The Guardian,atraditionally leftwing leaning British newspaper, a strong victory for May would give Europe a clear message: Brexit is happening and there's no going back. This way, according to the Financial Times– in favour of a May victory – minority groups won't weigh the Prime Minister down during negotiations.
The British press has reported that sources inside Downing Street say May called snap elections because she feared Corbyn's resignation, as (at least initially) he was considered a weak adversary. This view is slowly changing: if at the end of April the polls predicted that the Conservatives would win with a 20 point margin, the latest ones estimate that they won't even be able to win a majority of 326 seats, giving a number up to Labour.

How the British electoral system works

The Fixed-term parliaments act of 2011 establishes that general elections are to be held every five years (the last ones were in 2015) unless at least two thirds of Parliament votes in favour of snap elections. On the 19th of April 522 Members of Parliament (MPs) decided to go to the polls. The UK is divided into electoral colleges, each of which chooses its representative in the House of Commons – the upper house, the House of Lords, is instead an independent non elected body – therefore citizens don't vote directly for the head of state. Normally the party that wins the most seats forms the government and the head of the party becomes Prime Minister.

Getting Brexit right is crucial to our children’s future. From jobs to our schools, everything depends on securing the best Brexit deal. pic.twitter.com/Xe7n6ugZmV

The candidates

At the centre of her campaign is hard Brexit. She wants to abolish the common market, customs union and free movement of EU citizens in the UK – as well as wanting to reduce immigration in general. May says she wants to guarantee the rights of European workers as well as establish a "deep and special partnership" with the continent. According to the party's manifestothe funds the country won't give to the EU will be used to fight inequalities. Because whilst its economic programme contains typical rightwing recipes – sounds public finances, low taxes, free trade deals – much of the language is borrowed from the left, promising to work for a more equal society. Among the electoral commitments is the safeguarding of workers' rights, supporting the National Health Service (NHS, in grave crisis) and imposing limits on energy and gas bills. There is also the intention of tightening the gender pay gap and ethnic inequalities.
In environmental terms the Conservatives promise to respect the commitments taken to contrast climate changeunder the Paris Agreement. But if on the one hand they support the development of wind farms on the remote islands of Scotland, at the same time they don't consider the construction of onshore wind farms on a large scale a viable solution for the country. May wants to, instead, diversify the energy mix also with the extraction of shale gas.

The Labour candidate has been MP since 1983 representing Islington North, in London. A historic figure of the British Left, Corbyn was elected head of the party after its disappointing performance in the 2015 elections. According to his programme Brexit will happen but the rights of European citizens in the country will be guaranteed and some of the benefits of the single market will be preserved. Unlike the Conservatives, he hasn't committed to reducing immigration.
Special attention is given to workers' rights, in particular raising the minimum wage by 2020. Corbyn's manifestois centred on strengthening public institutions, increasing funds to the NHS, lowering university tuition fees, and re-nationalising services such as water, railways and the Royal Mail. To finance public spending taxes will be raised on wealth and corporations. Labour also wants to respect international commitments to reduce CO2 emissions, opposing frackingand working to cover 60 per cent of energy needs with renewable sources by 2030. It supports the rights of both domestic and farm animals (including maintaining restrictions on fox hunting, which May says she wants to reinstitute), those of women, with the evaluation of all government policies in terms of their gender impact, and LGBT ones.

The Lib Dems are the UK's third party: though the Scottish National Party (SNP) is the third party for number of seats in parliament, it is based only in Scotland. Currently the head of the centrist party is Tim Farron, the candidate most strongly against Brexit who has a promised a second referendum if he is elected – a remote possibility, even though if neither the Conservative nor Labour parties obtained a majority, the Lib Dems could be key in the formation of a coalition government (which happened in 2010 when Nick Clegg became Cameron's Deputy Prime Minister with disastrous results for the party's popularity).
The Lib Dems also want to redistribute wealth raising taxes on wealth as well as save the NHS. Their manifestois centred on investing more in education, which has seen cuts under the latest Conservative governments, and young people, for example through a programme to help them become homeowners. Among its environmental commitments, it wants to cut premature deaths by 40,000 by reducing air pollution levels and double the production of clean energy by 2030, covering 60 per cent of the national energy demand.

The other candidates

Other electoral candidates are Nicola Sturgeon of the Scottish National Party, the Scottish Prime Minister who want to call a second referendum on Scottish independence; Caroline Lucas and Jonathan Bartley of the Green Partywho want to form a centre-left coalition with Labour and the Liberal Democrats to oppose a hard Brexit and the Conservatives' austerity programme; and Paul Nuttall of UKIP(UK Independence Party), the Eurosceptic and anti-immigration party previously led by Nigel Farage who wants to limit the religious freedoms of the UK's many Muslim citizens, including banning the niqab and burka.
A key election for the United Kingdom, about to face one of the most important changes of the last 50 years. It is likely that Theresa May will be confirmed leader. But wasn't it Brexit that taught us that when people go to vote anything can happen?